Round-robin routing assumes all buyers are equal. In practice, they almost never are. One buyer pays $45 per lead and another pays $25. One has a sales team of ten and another is a solo operator. Weighted distribution is the mechanism that reflects these differences in how leads actually flow.
Setting up weights sounds simple — assign percentages — but the details of cap interactions and fallback behavior are where most implementations go wrong.
How weighted distribution works mechanically
Each buyer in a campaign gets a numeric weight. The router uses those weights to calculate each buyer's share of total leads over time. With buyers weighted 50/30/20, roughly 50 out of every 100 leads go to buyer A, 30 to B, and 20 to C. In practice, this plays out probabilistically rather than exactly, so in any given hour the split might be 48/31/21 — close enough to target over daily volumes.
Weights can be expressed as percentages that sum to 100, or as integers where the router calculates each buyer's share relative to the total weight sum. Either approach works; what matters is that the router recalculates correctly when buyers are added or removed.
The cap interaction problem
The most common failure mode in weighted routing is ignoring daily caps. If buyer A (50% weight) hits their cap at noon, a naive system either continues trying to deliver to them (and fails) or drops the excess leads. Neither is acceptable.
Cap-aware weighted routing solves this by dynamically re-weighting the remaining eligible buyers. When A caps out, leads redistribute between B and C at their relative weights — in this case 60/40 of remaining volume. This keeps delivery flowing without manual intervention and without wasting leads.
Weighted vs. other routing models compared
| Routing model | Best for | Cap interaction | Tools with native support |
|---|---|---|---|
| Round-robin | Buyers with equal value and capacity | Simple skip to next | Most routers |
| Priority order | Primary + fallback buyer setup | Move down list | Most routers |
| Weighted (LeadMove, $149/mo) | Buyers with different pricing or capacity | Cap-aware redistribution | LeadMove, LeadProsper ($499+), Boberdoo ($1,000+) |
| Ping/post auction | High-volume verticals with many competing buyers | Bid-based, no caps | Boberdoo, LeadProsper |
Choosing the right weights
Start weights based on the buyer's per-lead price and their stated capacity. A buyer paying $50/lead and handling 30 leads/day should get more weight than one paying $30/lead and handling 15/day. Review and adjust monthly based on actual conversion data — a buyer with high weight but low close rate is not maximizing your lead value. Weights are a starting point, not a permanent setting.
Combining weights with other routing rules
Weights apply after other filtering rules have narrowed the eligible buyer pool. A lead from Arizona first filters to Arizona-eligible buyers, then distributes among them by weight. If operating hours are also set, the eligible pool further narrows to buyers who are currently active. Weights then determine the proportional split within that filtered, active pool. This layering is what makes rules-based routing flexible without requiring separate workflows for every scenario.
Weighted distribution is the difference between a routing setup that reflects your actual buyer relationships and one that treats every buyer as interchangeable. Most agencies realize they need it the first time a top buyer complains about receiving the same volume as a trial buyer.